Alterations in DNA-dependent RNA polymerase I from rat liver accompanying ethionine administration

The activity of the template-engaged form of RNA polymerase I from livers of adrenalectomized rats was about 50-60% of that of normal control rats, and increased about 2-fold at 6 h after the administration of dexamethasone. However, no change was found in the activity of the ‘free’ form of RNA polymerase I or the template-engaged form of RNA polymerase II. Immunochemical studies using guinea-pig anti-(RNA polymerase I) serum disclosed that the total number of RNA polymerase I molecules did not vary during the treatment with dexamethasone. Cycloheximide caused a rapid decrease in the template-engaged form of RNA polymerase I activity in normal rats and in dexamethasone-treated (6 h) adrenalectomized rats, to the value in adrenalectomized rats, but affected it only slightly in adrenalectomized rats. The elongation rate of rRNA-precursor synthesis in liver nuclei was not affected by a change in the concentration of circulating dexamethasone. From these results, it is concluded that about half the rRNA-precursor synthesis in rat liver is regulated by glucocorticoids, probably through the synthesis of short-lived protein(s) which may play a role in conversion of the ‘dormant’ form of RNA polymerase I into the ‘engaged’ form.

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Stimulation of nuclear RNA polymerase I activity by a soluble factor isolated from young rat liver nuclei

AGE ◽

10.1007/bf02432198 ◽

1983 ◽

Vol 6 (4) ◽

pp. 106-112 ◽

Cited By ~ 2

Author(s):

Patricia Fitzpatrick-Dimond ◽

John A. Todhunter ◽

Sameeh S. Elridi

Keyword(s):

Rna Polymerase ◽

Rat Liver ◽

Rna Polymerase I ◽

Soluble Factor ◽

Nuclear Rna ◽

Liver Nuclei ◽

Young Rat ◽

Polymerase I ◽

Nuclear Rna Polymerase ◽

Stimulation Of

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Evidence for the transcription of physiologically inactive rat-liver nucleolar chromatin by Escherichia coli RNA polymerase

Bioscience Reports ◽

10.1007/bf01116378 ◽

1982 ◽

Vol 2 (3) ◽

pp. 155-161 ◽

Cited By ~ 3

Author(s):

Fu-Li Yu ◽

Annabella Barrett

Keyword(s):

Escherichia Coli ◽

Rna Polymerase ◽

Rat Liver ◽

Dnase I ◽

Rna Polymerase I ◽

E Coli ◽

Chromatin Template ◽

Nucleolar Chromatin ◽

Polymerase I ◽

Active Genes

Rat-liver nucleoli (10–15 pg DNA) were digested with either 0.6 or 3 units of DNase I for various times (up to 1 h). RNA synthesis was then measured in the absence or presence ol 3 units of Escherichia coli RNA polymerase. It was found that the nucleolar chromatin supporting the endogenous engaged RNA polymerase I transcription was compl-etely destroyed in 3 min with either concentration of DNase I. The nucleolar chromatin template transcribed by E. coli RNA polymerase retained 50% of its original capacity even 60 min alter 3 units of DNase I digestion. When hybridization experiments were conducted, it was found that the DNAs derived from both levels of DNase-Idigested nucleoli were incapable of forming hybrids with the labelled nucleolar RNA synthesized by the engaged RNA polymerase I from the untreated nucleoli. Since the engaged RNA polymerase I transcribes only the physiologically active genes of the nucleolar chromatin, and the RNA transcripts represent active gene product, these data suggest that DNase I digestion has completely destroyed the active genes of the nucleolar chromatin, and E. coli RNA polymerase is able to transcribe the inactive nucleolar chromatin template.

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Purification of rat liver and mouse ascites DNA-dependent RNA polymerase I

Biochemistry ◽

10.1021/bi00627a021 ◽

1977 ◽

Vol 16 (8) ◽

pp. 1655-1665 ◽

Cited By ~ 16

Author(s):

Michael I. Goldberg ◽

Jean Claude Perriard ◽

William J. Rutter

Keyword(s):

Rna Polymerase ◽

Rat Liver ◽

Rna Polymerase I ◽

Mouse Ascites ◽

Polymerase I

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Relationship between RNA polymerase I activity and ornithine decarboxylase in rat liver tissues

Biochemical Journal ◽

10.1042/bj2410169 ◽

1987 ◽

Vol 241 (1) ◽

pp. 169-174 ◽

Cited By ~ 2

Author(s):

M Urata ◽

N Suzuki ◽

T Hosoya

Keyword(s):

Rna Polymerase ◽

Ornithine Decarboxylase ◽

Rat Liver ◽

Protein Sequence ◽

Rna Polymerase I ◽

Rat Liver Nuclei ◽

Liver Nuclei ◽

Polymerase I ◽

The Relationship ◽

Liver Tissues

In order to examine the relationship between RNA polymerase I and ornithine decarboxylase (ODC), three lines of experiments were performed, with the following results. The glucocorticoid-induced increase of RNA polymerase I in rat liver nuclei was not abolished by administration of inhibitors of ODC synthesis and activity, namely 1,3-diaminopropane and 2-difluoromethylornithine respectively. Anti-ODC antibody did not cross-react with RNA polymerase I solubilized from rat liver nucleoli, indicating the absence of a common protein sequence in these enzymes. The ODC preparation which was treated with transglutaminase in the presence of putrescine could not stimulate the activity of RNA polymerase I in nuclei of liver and prostate. All these results suggest that the increases in ODC protein or activity are not a prerequisite to the increase in RNA polymerase I after hormonal or physiological stimuli, but rather that the increases in both enzymes are separate responses to the primary stimuli.

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